some other brit**h changes in which most north american dialects do not participate:
the shift of/æ/to/ɑ/(the so-called"broad a")before/f/,/s/,/θ/,/e/,/z/,/v/alone or preceded by a homorganic nasal.th** ** the difference between the brit**h received pronunciation and american pronunciation of bath and dance.in the united states,only eastern new england speakers took up th** modification,although even there it ** becoming increasingly rare.
the realization of intervocalic/t/as a glottal stop[ʔ](as in[bɒʔəl]for bottle).th** change ** not universal for brit**h and ** not considered a feature of received pronunciation.th** ** not a property of most north american dialects.newfoundland ** a notable exception.
on the other hand,north american has **ne some sound changes not found in the standard varieties of speech:
the merger of/ɑ/and/ɒ/,making father and bother rhyme.th** change ** nearly universal in north american occurring almost everywhere except for parts of eastern new england,hence the boston accent.
the merger of/ɒ/and/ɔ/.th** ** the so-called cot-caught merger,where cot and caught are homophones.th** change has occurred in eastern new england,in pitt**urgh and surrounding areas,and from the great plains westward.
for speakers who do not merge caught and cot:the replacement of the cot vowel with the caught vowel before voiceless fricatives(as in cloth,off[which ** found in some old-fashioned varieties of rp]),as well as before/ŋ/(as in strong,long),usually in gone,often in on,and irregularly before/ɡ/(log,hog,dog,fog[which ** not found in brit**h at all]).
the replacement of the lot vowel with the strut vowel in most utterances of the words was,of,from,what and in many utterances of the words everybody,nobody,somebody,anybody;the word because has either/ʌ/or/ɔ/;[7]want has normally/ɔ/or/ɑ/,sometimes/ʌ/.[8]
vowel merger before intervocalic/ɹ/.which vowels are affected varies between dialects,but the mary-marry-merry,nearer-mirror,and hurry-furry mergers are all widespread.another such change ** the laxing of/e/,/i/and/u/to/ɛ/,/ɪ/and/ʊ/before/ɹ/,causing pronunciations like[pɛɹ],[pɪɹ]and[pjʊɹ]for pair,peer and pure.the resulting sound[ʊɹ]** often further reduced to[ɝ],especially after palatals,so that cure,pure,mature and sure rhyme with fir.
dropping of/j/** extensive than in rp.in most north american accents,/j/** dropped after all alveolar and interdental consonant,so that new,duke,tuesday,resume are pronounced/nu/,/duk/,/tuzdeɪ/,/ɹɪzum/.
æ-tensing in environments that vary widely from accent to accent;for example,for many speakers,/æ/** approximately realized as[eə]before nasal consonants.in some accents,particularly those from philadelphia to new york city,[æ]and[eə]can even contrast sometimes,as in yes,i can[kæn]vs.tin can[keən].
the flapping of intervocalic/t/and/d/to alveolar tap[ɾ]before unstressed vowels(as in butter,party)and syllabic/l/(bottle),as well as at the end of a word or morpheme before any vowel(what else,whatever).thus,for most speakers,pairs such as ladder/latter,metal/medal,and coating/coding are pronounced the same.for many speakers,th** merger ** incomplete and does not occur after/aɪ/;these speakers tend to pronounce writer with[əɪ]and rider with[aɪ].th** ** a form of canadian ra**ing but,unlike extreme forms of that process,does not affect/aʊ/.in some areas and idiolects,a phonemic d**tinction between what elsewhere become homophones through th** process ** maintained by vowel lengthening in the vowel preceding the formerly voiced consonant,e.g.,[læ:·ɾɹ̩]for"ladder"as opposed to[læ·ɾɹ̩]for"latter".
both intervocalic/nt/and/n/may be realized as[n]or[ɾ̃],rarely making winter and winner homophones.most areas in which/nt/** reduced to/n/,it ** accompanied further by nasalization of simple post-vocalic/n/,so that v/nt/and v/n/remain phonemically d**tinct.in such cases,the preceding vowel becomes nasalized,and ** followed in cases where the former/nt/was present,by a d**tinct/n/.th** stop-absorption by the preceding nasal/n/does not occur when the second syllable ** stressed,as in entail.
the pin-pen merger,by which[ɛ]** ra**ed to[ɪ]before nasal consonants,making pairs like pen/pin homophonous.th** merger originated in southern american but ** now also sometimes found in parts of the midwest and west as well,especially in people with roots in the mountainous areas of the southeastern united states.
some mergers found in most varieties of both american and brit**h include:
the merger of the vowels/ɔ/and/o/before 'r',making pairs like horse/hoarse,corps/core,for/four,morning/mourning,etc.homophones.
the wine-whine merger making pairs like wine/whine,wet/whet,wales/whales,wear/where,etc.homophones,in most cases eliminating/hw/,the voiceless labiovelar fricative.many older varieties of southern and western ame still keep these d**tinct,but the merger appears to be spreading.